William o



W. O. DWYER.

STATIONARY INDUCTION APPARATUS.

PPLICATION FILED FLB. 27, I920. 1,352,360, PatentedSept. 7,1920.

Fig. I. m

Volts.

Inventor-t William O Dw yer;

H is Attorney.

UNITED STATES? WILLIAM C.

PATENT OFFICE.

DWYER,-. OF PITTSFIELD, :MASSACHUSETTS, ASSIGNOR TO GENERALELECTRIC'COMPANY', AL CORPORATION OF NEW YORK.

H STATIONARY INDUCTION APPARATUS; 1

"To all whom it may concemf v Be it known 'that I, VVI IQIAM DwYnn; asubject of the King ofGr'e'at Britain,residing at Pittsfield county ofBerkshire, State of Massachusetts, have invented certain new and usefulImprovements in Stationary Induction' Apparatus, ofiwhieh the followingis a specification. My i ent o e t sfjto s i n y i tion apparatus andfor its general ob; j s mpr v s a ran ment 0f "p rt w a w re: is p ducedla" d vic of. this character, having better electrical v propertiesfatfles's cost and "iwith more "'efiioient utilization of thematerials of construction than hasheretofore beenaccomplished.

' It has heretofore been 'propose dto reduce the insulationemployed inwindings; particularly those having one end "grounded, by bringing theline lead'into conducting'relation with the windings atthe central pointof a windingstack, as shownin the. application of O. 1Stephens, SerialNo. 137,548, in order that'such connection will;v be as far removedfrom'the end iron of thecore as possible. connecting each side of thewinding stack in parallel frorn'this central point the charging currentalso isreduced.

By my invention ho 'yeverg a still more desirable electrical effect isaccomplishedf or Iv employ a condenser elem'ent disposed among thewindings at the middle point of the winding stack'whi'chelectrostatically imposes a desired distribution of voltage throughoutthe coils and coil stack so that it is impossible for-high initial andsubse: quent resonant voltages tobuild up in the windings or'coils bysteep wave fronts. I may thus considerably decrease the quantity ofinsulation previously employed and yet have the desired margin ofsaiety.

It will readily be appreciated that among the advantages had from thisconstruction is animproved space factor due to the need for'lessinsulation. together with a more economical use of the material ofconstruction such as the iron and copper commonly employed.

Other advantages and objects of my invention will appear-"from thefollowing detailed description when taken in connection with theaccompanying drawing in which:

Figure 1 shows a view mainly in vertical section of a transformer havingthe high voltage winding constructed to embody my :planator'y' diagrams.

Specification of Letters Patent. Patented Sept, 7, 1920, Applicationfiled Februar 27, 1920; Serial a, 361,702.

invention. Fig. 2 is'a horizontal mid-section of the transformer shownin Fig. 1. lgs. 3 andfl show details in the constructlons employed. Andi ileferring iPiW Fto the drawing, and partlcularly to Fig. "1,Ihave;shown a transformer havingz a, core 10; provided with a cylindrical l'owvo'l'tagewinding 11 arranged aboutthe cent 1 legf12 of the core.Exterlorly of this low oltage winding 11 is'the high Y9ltage ;W.- 1ng13,,which'in accord ance with'my p nt invention is. preferablyofthe'diskf'cOil construction; 1 The winding 13 is arrangedto ,have a.terminal leading we supply line adapted for connection to' the middlepoint of the windingstack, as shown at 14. I Since my invention-isparticularly applicable totransformers having one terminal "of the highvoltage winding groundedg th'ejtwo end's of the coil stack areaccordingly-Q} indicated as connected to ground v as at: 15 and 16. Theooils of winding 13 are arranged and connectedso that the current fromthe line terminal 14, at any instant, flows in thesame direction aboutthe winding axis" which is a a 'fsingle' straight line) whether iconsider that portiondn the group of coils :above" the center or that inthe 'groupbelow the center. Hence the magnetic flux in the coreengendered by the high voltage current has everywhere the samedirectionetlany-instant.

At the middle of the high'voltage coil stack, I insert the substantiallycircular 'conducting-plate 2Q, to eiiect-by condenser action thepotential distribution across the upper and lower portions of the coilstack in accordance with my invention. This plate 20 is split, asindicated at 21 in'Fig. 2, the ends being-insulated apart by means ofinsulation 22 to prevent a short circuited current from flowing in thiselement; and is also conductivcly connected to the line terminal '14 asindicated at 23.

The plate 20 is preferably made from one strip of conducting material,such as steel or copper, and is incased in an insulating jacket 24 asshown in Fig. 3 in a manner substantially similar to that on the coilsin the winding 13. By reason of the splitting of the plate 20, as at 21,it may with advantage in some instances be made the first turn ofwindings in the upper and lower groups of coils of the coil stack sincethe Figs.' 5 and 6 are ,ex-

-sulatingj'acket 34. The conductors 80, form the plate element, but allwill be cut through at some point precisely similar to the point 21 inplate 20. plate element of this type is connected to the line by meansof the conductor .23.

' When inoperation, a conducting plate of this type in the center of thecoil stack, draws a 'leading'or charging current from the lineelectrostatically imposes a substantially uniform potential distributionthroughout 'both the upper and lower ;portions of the coil stack.Thiswill be readily comprehended by reference to Figs. 5: and 6. In Fig.5 Idhave drawn at E lines to represent the electrostatic flux(neglecting edge efiects) emanating from the charge on plate 20 foragiven instant; the broken lines S being similarly drawn to denote theequipotential surfaces corresponding to the lines E. Since the plate 20and the yokes of core 10 co rrespond to the elements of a condenser whenthe plate 20 is charged, the active portions of which elements aresubstantinally planes, the-electrostatic distribution of thepotential-across the space intervening between these elements will be atsubstantially a uniform rate. The windings 13 and 13 inserted in thesespaces are, by this condenser action, themselves brought to theirdesired potential by electrostatic induction without-drawing a chargingcurrent from the line, or what is the same thing rcgarded in a differentaspect, the shunt capacitance of the windings have been reduced to asubstantially negligible value.

In Figs. 6 I have plotted the potential of the coilslagainst turns,when-my invention is applied. Itis thus seen that for the mean turn ofeachcoil a substantially uniform rate of distribution is accomplished.

. Having now described an embodiment of my invention which is at presentthe best means known to me for carrying the same into efiect, I wouldhave it understood that this is merely illustrative and that I do not.mean to be limited thereby to the precise cally imposing throughoutsaid paths a desired potential distribution.

2. An electrical winding arranged to be supplied with current atsubstantially its middle point and to conduct the same in multiple pathsdiverging from said middle point. advancing in the same direction aboutthe winding axis, having a condenser element located at said middlepoint and conductively related to said windings.

3. In an electrical apparatus, the combination with a winding stackhaving a gle rectilinear winding axis, of a terminal connection atsubstantially the middle of said stack, saidwinding being arranged toconduct current in parallel paths, one for each section at the side-ofsaid connection, both to advance in the same direction about saidwinding axis, and a condenser element located at the middle of saidwinding stack arranged to electrostatically induce a substantiallyuniform potential distribution throughout each Winding section.

4. In a transformer and the like, the combination with a core, of a highvoltage winding composed of a stack of disk-coils having a singlerectilinear winding axis, a conducting element having approximately thedimensions of a disk coil located at sub stantially the mid point ofsaid stack, said element being conductively connected directly to thelineand to the coils at each side thereof, the coils at each side ofsaid element arranged to conduct current in the same direction aboutsaidwinding axis.

In witness whereof, I have hereunto set my hand this twentieth (20th)day of February, 1920.

7 WILLIAM O. DWYER.

